Over-the-needle catheters or over-the-needle IV catheters (such as that described in U.S. Patent Publication No. 2005-0096592, filed Oct. 31, 2003 to Carlyon et al.) are used for peripheral intravenous entry into the vasculature of a patient. The disposable medical product is packaged as an assembly of a catheter adapter with its catheter, and a needle/hub assembly that is arranged with respect to the catheter adapter so the needle passes through the catheter tube. The needle also extends a slight distance beyond the distal tip of the catheter tube so as to provide a sharpened point for penetration through the skin of the human or animal being catheterized.
After the catheter adapter with its catheter, and a needle/hub assembly are inserted into the vasculature or blood vessel of the patient, blood flows due to the vascular blood pressure through the hollow needle and into the needle hub, sometimes referred to as flashback. Typically, the needle hub is arranged and configured so the medical personnel are provided a visual indicator of the blood flashback. This visual indicator is used to indicate that the tip of the needle and thus the distal end of the catheter tube is disposed in the blood vessel. In one technique, the needle hub includes a chamber that is fluidly coupled to the needle and is made at least in part of a transparent material so that the blood flashback into the chamber is visually apparent to the medical personnel.
Even though such chambers are transparent, blood in the flashback chamber of these devices can sometimes be difficult to visualize in certain situations such as low light conditions or against darker backgrounds. It thus would be desirable to provide a new vascular access device such as an IV catheter device with enhanced flashback visualization. It would be particularly desirable to provide such a device that provides a high-contrast background to maximize flashback visibility. It would be further desirable to provide a device that facilitates earlier detection of blood or other fluids in the flashback chamber with greatly improved flashback visibility when used in low light situations or on patients with dark complexions. It also would be desirable to provide such a device that is less complex in stricture, manufacture and operation as compared to prior art devices. Also it would be desirable that such methods would not require users to have higher skills than those who ordinarily use such catheter devices.